[BUG] 71.0.0 fails with `'importlib_metadata' has no attribute 'EntryPoints'` on Python 3.8

[bmcalary-atlassian]

setuptools version

71.0.0

Python version

3.8

OS

Ubuntu 20.04

Additional environment information

No response

Description

This started a few hours ago when our pipeline picked up 71.0.0, works fine on 70.3.0.

python3 -m pip install --upgrade --no-cache-dir --no-color --no-input --upgrade pip packaging setuptools python-debian
Requirement already satisfied: pip in /usr/local/lib/python3.8/dist-packages (24.1.2)
Requirement already satisfied: packaging in /usr/local/lib/python3.8/dist-packages (24.1)
Requirement already satisfied: setuptools in /usr/local/lib/python3.8/dist-packages (71.0.0)

python3 -m pip install --no-cache-dir --no-color --no-input https://s3.amazonaws.com/cloudformation-examples/aws-cfn-bootstrap-py3-latest.tar.gz --upgrade
Collecting https://s3.amazonaws.com/cloudformation-examples/aws-cfn-bootstrap-py3-latest.tar.gz
  Downloading https://s3.amazonaws.com/cloudformation-examples/aws-cfn-bootstrap-py3-latest.tar.gz (549 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 549.6/549.6 kB 690.9 kB/s eta 0:00:00
  Preparing metadata (setup.py) ... error
  error: subprocess-exited-with-error

  × python setup.py egg_info did not run successfully.
  │ exit code: 1
  ╰─> [10 lines of output]
      Traceback (most recent call last):
        File "<string>", line 2, in <module>
        File "<pip-setuptools-caller>", line 14, in <module>
        File "/usr/local/lib/python3.8/dist-packages/setuptools/__init__.py", line 19, in <module>
          from .dist import Distribution
        File "/usr/local/lib/python3.8/dist-packages/setuptools/dist.py", line 30, in <module>
          from . import _entry_points
        File "/usr/local/lib/python3.8/dist-packages/setuptools/_entry_points.py", line 44, in <module>
          def validate(eps: metadata.EntryPoints):
      AttributeError: module 'importlib_metadata' has no attribute 'EntryPoints'
      [end of output]

Expected behavior

No error

How to Reproduce

See Description

Output

See Description

[jaraco]

This behavior is by design. Setuptools now will prefer installed packages over its vendored ones, but it can't yet declare them. That means that if you have an installed dependency but it's older than the one setuptools needs, it will not work.

The workaround/fix is to install these dependencies when installing setuptools. You may be tempted to install setuptools[core], but please don't as that's unsupported and will likely break in the future.

Either that, or ensure that there aren't older versions of those dependencies installed.

Eventually, we plan to have setuptools declare (and thus install) its own dependencies so you don't have to do that, but for Setuptools to do that, we first have to solve pypa/packaging-problems#342 (an ongoing effort).

[bmcalary-atlassian]

Thanks, importing those, specifically importlib_metadata fixed the problem. Shame its not automatic at the moment.

Thanks for the quick response. Much appreciated.